Extended case-control study results on thromboembolic outcomes among transdermal contraceptive users☆☆☆★
Received 11 November 2009; accepted 9 December 2009. published online 25 January 2010.
Abstract
Background
We extended an earlier study that found a twofold higher risk of venous thromboembolism (VTE) associated with the transdermal contraceptive system relative to norgestimate-containing oral contraceptives (NGM-OC).
Study Design
This case-control study identified potential cases of VTE, acute myocardial infarction (AMI) and stroke from 24 months of additional health care claims, with adjudication via medical records. Randomly selected controls were matched to cases on age (15–44 years) and characteristics of contraception use. Conditional logistic regression models provided odds ratios (ORs) and 95% confidence intervals (CIs).
Results
The transdermal contraceptive system was associated with a twofold higher risk of VTE (OR 2.0; 95% CI 1.2–3.3) compared with users of NGM-OC. The OR for stroke was 0.6 (95% CI 0.1–3.2) and for AMI 1.2 (95% CI 0.3–4.7).
Conclusion
This extension was consistent with the earlier study, showing a twofold increased risk of VTE associated with use of the transdermal contraceptive system relative to NGM-OC.
bDepartment of Community Health, The Warren Alpert Medical School of Brown University, Providence, RI 02912, USA
cDepartment of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
Corresponding author. i3 Drug Safety, Waltham, MA 02451, USA. Tel.: +1 781 472 8497; fax: +1 781 472 8464.
☆ This study was funded by a research contract between i3 Drug Safety and Johnson & Johnson Pharmaceutical Research & Development, LLC. The contract granted i3 Drug Safety oversight of the study conduct, reporting and interpretation, as well as final wording of any resulting manuscripts.
☆☆ An abstract (<300 words) of this paper was presented at the International Society for Pharmacoepidemiology's annual meeting in August 2009 in Providence, RI.
★ Disclosures: Dr. Dore, Ms. Norman, Ms. Loughlin and Dr. Seeger are employees of i3 Drug Safety and holders of stock and stock options in UnitedHealth Group (the parent corporation of i3 Drug Safety).
ABSTRACT